Shell-banding machine



1950 A. F. REHNBERG ET AL 2,517,598

SHELL-BANDING MACHINE Filed Jan. 18, 1943 5 Sheets-Sheet l g 1950 A. F. REHNBERG ETAL 2,517,598

SHELL-BANDING MACHINE Filed Jan. 1a, 1943 s Sheets-Sheet 2 Aug. 8, 1950 Filed Jan. 18, 1943 A. F. REHNBERG ETAL ,SHELL-BANDING MACHINE 5 Sheets-Sheet 4 g- 1950 A. F. REHNBERG ETAL 2,517,593

SHELL-BANDING MACHINE Filed Jan. 18, 1943 5 Sheets-Sheet 5 77 Inn/awn:

Patented Aug. 8, 1950- SHELL-BANDING MACHINE Axel F. Rehnberg, Rockford, Ill., and John Nelson,

Santa Monica, Calif., assignors to Rehnberg- Jacobson Mfg. 00., Inc., Rockford, 111., a corporation of Illinois Application January 18, 1943, Serial No. 472,740

3 Claims.

i This invention relates to a new and improved shell-banding machine.

The copper rifling band, which is larger in diameter than the shell and must be entered with a tight fit in an annular groove in the shell, and firmlyheld against turning by tight engagement with serrations in the groove, has heretofore been slipped over the shell to the groove and thenin one operation compressed by a number of slides moving radially inwardly so as to cause the band to enter the groove and grip the serrations. It has been found that there were too many rejections of shells handed in that way, due to crystallization of the metal in the band. It is, therefore, one of the principal objects of our invention to provide a shell-banding machine in which, the band is compressed only very slightly in the first operation and is thereafter indexed before the next heavier compression, there being preferably a number of subsequent compressions with automatic indexing between compressions to permit uniform metal flow, prevent crystallization of the copper, and provide thorough penetration into the serrations.

Another object of our invention is to provide a machine of the kind mentioned in which movement of the jaws for the first squeeze is positively limited for a partial squeeze, suiiicient only to flow the ring into engagement with the tips of the serrations, the jaws in the subsequent squeezes being controlled only as to the pressure applied, the shell being turned slightly between these various operations, as previously stated, so

that after the last squeeze the band is certain of being swaged solidly in place in the groove and the metal of the band having flown uniiormly is not apt to be crystallized.

Another object of our invention is to provide a machine of the kind mentioned, in which the plurality of jaws movable radially inwardly for compression of the band onto the shell are all operated by a single ram movable axially, the jaws being on lever members swingable inwardly along radial lines, and the ram being centrally arranged on the vertical axis of the machine and operated hydraulically by a single piston and cylinder to operate the jaws by oscillation of their lever members, whereby to secure maximum compactness, simplicity, and economy of construction.

Still another object of our invention is to provide a machine of the kind mentioned which may be quickly and easily changed to handle all sizes of projectiles, from 20 mm. to and including '75 mm., either armor piercing or high explosive types, the change-over ferent set of jaws, the jaws being removably secured to the inner ends of slides actuated by the lever members.

Still another object of our invention is to pro vide a machine of the kind mentioned, in which a mandrel is provided for entry into the bore of high explosive type shells for support of thewall thereof in the vicinity of the band receiving groove, so that there will be no danger of distortion of the shell in theapplication of the band.

The invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a side view of a machine made in accordance with our invention;

Figs. 2, 3, and 4 are views of the butt portion of a shell showing the band in section before application, at an intermediate stage of applica-- tion, and as finally applied;

Figs. 5 and 6 are cross-sections on the 5-5 and 6-6 of Figs. 3 and 4, respectively;

Fig. '7 is a central vetrical section through the machine illustrating the relationship of the ram to the lever members which operate the band compressing jaws;

from one size to another 1 being mainly only a matter of substituting a diflines Fig. 8 is a top view of the machine with a portion of the cover broken away to better illustrate the construction;

Fig. 9 isa fragmentary vertical section on the broken line 9--9 of Fig. 8 i

Fig. 10 is an enlarged sectional detail taken on the line ID-l0 of Fig. 9;

Fig. 11 is a view similar to Fig. 10 showing the parts in a moved position;

Fig. 12 is an electrical and hydraulic circuit diagram of the machine, and

Fig. 13 is a fragmentary vertical section of another machine, illustrating the mandrel for sup-u port of the thin walls of high explosive type shells.

Similar reference numerals are applied to cor-.

responding parts throughout the views.

rifling band therefor.

vent turning thereof when the band has been applied. The band before application is larger, in diameter than. the shell so that it can he. slipped easily over the shell to the groove, as. illustrated in Fig. 2. Then, in accordance with our invention, the band is given a partial squeeze to flow the band only to the top of the serrations, as illustrated in Figs. 3 and 5, the circumferentially spaced protruding portions [5 on the periphery of the band being what may be termed flash, that being the metal in the spaces between the jaws. In this partial squeeze the band has taken hold of the serrations well enough to insure the band turning with the shell in the indexing of the latter between squeezes, in accordance with our invention. The. shell with the band thus partially applied is indexed so that the projecting flash portions [6 on the band will be compressed by the jaws in the next squeeze, which is a heavier squeeze and may or may not be the final squeeze. Usually, however, there is one light partial squeeze and two heavy squeezes, and, as will soon appear, the machine herein illustrated is constructed for such operation. The indexing of the shell between squeezes permits uniform metal flow, prevents crystallization. of the copper, and provides thorough penetration. into the serrations. The band as it appears when finally applied is illustrated in Figs. 4 and 6.

The. machine, as illustrated in Figs. 1, '7, 8, and 9, comprises a hollow base IT, on the. top of which is supported a spider-shaped casting l8, providing five radial guides I9 in equally spaced relation for the same number of slides 25 which operate the band compressing jaws 2|. Each slide has a cooperating lever member 22 pivoted intermediate its ends, as at 23, on the spider l8 and operatively connected with the slide at its bifurcated upper end 24 in which a block 25 is slidably received, the block being pivoted on a crosspin 26 on the slide. Acradle 21 is suspended from the spider 18 within the base I! and has spring pressed plungers 28- mounted in the side walls thereof engaging the levers 22 near the lower ends, so as to keep the shoes 29, which are pivoted on the lower ends of the levers, as at 30, in close working contact with wedge blocks 3!: demountably secured on the flat faces 32 of theram 33. The ram isinternally threaded at 34 for adjustable threaded connection with the upper end of a piston rod 35, av nut 35 threaded on". the rod being tightened against the bottom oi the ram to lock it in adjusted position. The cradle 21 supports a hydraulic cylinder 31 in which a. piston 38 on the lower end of the rod 35 operates. and outlet of oil to and from the opposite ends of the cylinder. As will presently appear, oil is. delivered: under pressure to the lower end of the cylinder 3'! to raise the piston 38 and ram 33to cause the jaws 2| to move radially inwardly toward one another and thereby compress the band B on the shell. S. In. the first squeeze the length, of the, stroke of. the piston and ram is regulated, as will. later appear, so that the band is compressed only to the point of engagement with the serrations [5 in the groove I4 on the shell, so as. to be held against turning with respect to the shell, but in the subsequent squeezes there isno regulation of the stroke but only regulation of the pressure applied by the jaws. That is to say, the jaws are permitted in the second and third squeezes to apply pressure to the band until the pressure in the cylinder 3.? builds up to a predetermined amount, whereupon the pressure is released and oil under pressure is delivered to the upper end of the cylinder 31 for return of the ram 33.

The ram 33 is guided at. circumferentially Pipes, indicated at 39, are for inlet spaced points by segmental-shaped bearings 40 projecting radially inwardly from the side walls of the cradle El between the wedge blocks 3i. A plate 4| is removably secured on the upper end of the ram 33 and has the lower end of a rod 42 adjustably and detachably connected therewith, as indicated at 43. This rod is reciprocable in a vertical guide 44 provided therefor in the spider l8 and has rack teeth 45 provided on one side of the upper end portion thereof for meshing engagement with a pinion 45. This pinion is part of a cluster with the larger gear 47, which meshes with the rack 48, horizontally disposed and slidable freely in a guide 49 on top of the spider l8. The rack 48 has rack teeth 5|] on one side of the other end thereof remote from the gear cluster 4B -4| meshing with a gear 5| formed on a hub 52, in which a spring pressed pawl 53 is slidably mounted for cooperation with the teeth of a ratchet wheel 54 secured on the upper end of a tubular shaft 55. The ratchet wheel 54 has two cams 56 and 51 turning therewith for operation of. the plungers 58 of two limit switches S3 and S1, respectively, which, as will presently appear, are included in the electrical control system of the machine and are so illustrated in Fig. 12'. The shaft. is not turned in the upward movement of the ram-33, inasmuch as such movement causes counterclockwise turning of the gear 5|, and in such turning the pawl 53 rides idly over the teeth of. the ratchet wheel 54. However, in the return stroke of' the ram, when the gear 5| is given clockwise rotation, the pawl 53 operatively engages a tooth of the ratchet wheel and causes. the shaft 55 to. be. turned through a predetermined'angularity. A gear 55' keyed on the lower end of'the shaft 55 turns with it and meshes with a gear 55 detachably secured on the lower end of a; short. vertical shaft 60 mounted in a bearing bushing 6| removably secured in a hole provided therefor in the spider l8, as by means of a set screw 52'. A pinion. 63 is fixed on the upper end of the shaft and transmits intermittently drive to a ring gear 64, namely, in each return movement: of the ram 33. The ring gear 54 forms part of a. rotary work holder or support and has an upwardly projectinghub portion rotatable freely inabearing' 55 in the center of the spider [8. Two rings Stand 6? are detachably fastened together and to. the hub of the gear 64 above the bearing: 65 so that they serve to support the gear 54'; The ring'fifi' has a center hole 58 large enough to admit the lower end of the shell S freely but too small to allow the band B in its original uncompressed. size to pass through, whereby to pro-- vide a support on top. of the ring 66 for the band B prior to the operation of the machine to apply the band, the hole 58 being large enough to permit passage of. the banded portion of the shell.

therethrough at the conclusion of the banding operation, so that the banded shells may be dropped." down into a chute 69 for discharge from the machine. pivoted, as at H, on the ring gear 64 and ring, 61 andisnormally held in the operative position, shownin Fig. 10, under the action of a coiled. torsion spring 12 which encircles the pivot pin II and has one end fixed to the ring 54 and the other movable end fixed to the pivot pin H. An arm '13 projects from the work support on the opposite side of the pivot H and is arranged to have slidable engagement with a cam 14 in the manner illustrated. in Fig. 11 when the ring gear 64 is: turnedin its final indexing operation after the.

. third squeeze. When the arm i3 slides along the.

A swingablev work support 10 is.

cam 14, the work support Ill is held in an out-ofthe-way inoperative position, as shown in Fig. 11, allowing the banded shell S to drop by gravity into the chute 69 for discharge from the machine. The work support is shown in Fig. 10 in its operative position at the commencement of the cycle, and, as will soon appear, after the first squeeze or partial squeeze the gear 64 is turned through approximately 120 in a counter-clockwise direction from the position of Fig. 10, so as to turn the shell with the partially compressed band thereon through one-third of a turn preparatory to the second squeeze. Then after the second squeeze the gear 64 is turned again through 120 so as to index the shell through another third of a turn preparatory to the third and final squeeze. This indexing of the work between squeezes, as previously pointed out, permits the metal to flow uniformly and crystallization is prevented, and the band is caused to grip the serrations with substantially the same tightness throughout its circumference. After the third and final squeeze the gear 84 is turned again through 120, back to the original position shown in Fig. 10, and it is during that movement that the work support Hi is moved out of the way, as illustrated in Fig. 11, to allow the banded shell to drop out. It will, of course, be understood that we may dispense with the chute 69, where it is not desired to have the banded shells dropped into a container for fear of having the shells and bands thereon nicked by such handling, and in that event the only change necessary is to omit the cam 14 so that the work support 18 always remains in the operative position shown in Fig. 10. The operator in such event will, of course, have to remove the banded shells by hand. The cam 14 is supported on two spaced and substantially parallel vertical arms 15, which project upwardly from plate 16 removably secured onto the lower end of a stationary shaft 11, which extends upwardly through the tubular shaft 55 and is secured at its upper end, as at i8, in a boss 19 on a plate 88 fastened to the top of the guide 38. The shaft "ll has an annular flange 8| integral with the lower end portion thereof, and this flange forms a support for the lower end of a tubular shaft 55 and gear 55 keyed thereon. A screw 82 serves to fasten the plate 16 onto the lower end of the shaft fl, and when it is desired to remove the cam M, this screw can be removed to allow the plate 16, carrying the cam, tobe removed. Difierent thicknesses of shims 83 may be fastened on the upper face of the work holder 10 to support the shell at a higher or lower elevation, depending upon the spacing of the band receiving groove with respect to the lower end of the shell. In that way the machine can be easily adjusted to suit different requirements. The top plate 84, which is removably secured, as at 85, on top of the spider l8, has an enlarged center hole 86 through which the shells may be entered and in certain instances removed after banding. Acover 81 is shown in Figs. 1 and 7 to enclose the switches S1 and S3 and the other switches S2, S4, and S5 and the moving parts of the machine associated therewith. The top plate 84 also forms a support for the guide 89 which is disposed inside the cover 87.

In Fig. 13 we have illustrated an expander type mandrel 88 insertible in the bore 89 of high explosive type shells, like that indicated at S, to support the thin walls of the shells and prevent distortion thereof in the application of bands thereto. It will be understood that although a 6 small portion of the machine is illustrated inthis figure, the machine, except for the mandrel 88 and its cooperating plunger 90, is generally the same as that previously described, there being slides 28 movable radially inwardly in the spider I8 to cause the jaws 2| on the inner ends of these slides to compress the band B into the groove M in the shell, and there being also a ring gear 64' forming part of the work holder rotatable in the bearing 65 and arranged to be indexed between squeezes, similarly as the ring gear 64. The swingable work support Ill, previously described, is, of course, eliminated, and also the cam 14 for operating the same, and instead of the rings 66 and 61 two rings 66' and 81' are provided, detachably secured together and to the ring gear 64' to support the latter against displacement downwardly from the bearing 65. The center hole 68 in the ring 86' is large enough to receive the lower end of the shell, which rests on a work supporting ring 91 fastened to the bottom of the ring 66'. The grooved portion [4 of the shell is thus exposed above the ring 88 in the plane of operation of the jaws 2| to receive the band B. The mandrel 88 is supported on the ring ill to project up into the bore 89 slightly beyond the grooved portion of the shell. Theplunger 90, which cooperates with the mandrel to expand it, is reciprocable and rotatable in the bore 92 of atubular guide 93 carried on and projecting upwardly from a plate 4| detachably secured to the upper end of the ram 83. This plate corresponds to the plate ll previously described, and has the rod 42 adjustably connected therewith, which has the rack 45 on the upper end thereof forming a part of the indexing mechanism. A coiled compression spring 94 is housed inside the guide 93 and tends normally to urge the plunger upwardly for expansion of the mandrel 88. When the ram 33 is in its retracted position, as at the commencement and end of a cycle of squeeze operations, the spring 94 does not exert sufficient pressure on the plunger 90 to cause the mandrel 88 to grip the shell tightly, and there is, therefore, no appreciable interference with the easy removal and loading of work. However, it requires very little movement of the ram 33 upwardly on the working stroke to increase the spring pressure against the plunger 90 sufficiently for the mandrel 88 to grip the work tightly and thus provide ample support for the thin walls of the shell to prevent compression thereof in the compression of the band. On the other hand,

there is no danger of the mandrel causing expansion of the shell, inasmuch as the plunger 90 is not operated positively but the spring 94 yields when the resistance to movement of the plunger.

because it is in the retracting movements of the,

ram 33 that the indexing occurs and the spring pressure 94 against the plunger 9|! is, therefore, reduced during the indexing operation, thus allowing the plunger 98 to turn freely with respect to its guide 93 if the mandrel 88 should not turn with respect to the plunger.

Referring now to Fig. 12 for a better under-,

standing of the operation of the machine, an oil pump is shownat95 arranged tobe operated eone,

tinuously by an electric motor 96 to serve as a source of oil under pressure. The oil is pumped from a sump 91, and so long asthe plunger controlled valve V3 is open, the oil: is discharged idly back into the sump. To start the cycle of three squeeze operations, one soft and two hard, the operator closes switch S7 to energize relays R1 and R2. The operator keeps the switch S7- closed long enough for the ram 33 to rise far enough to close switch S4. Valve V4 is closed by reason of the energizationof its solenoid by relay R2.- This causes valve V3 to shift, closing its drain passage so that the full head of the pump 95 is delivered to valves V2 and V1. The closing of relay R1 energiz'es the solenoid of valve V1 causing its valve plunger to rise to the opposite extreme from that shown, so that fluid is delivered from valve V1 to shift the plunger of valve V2 to its lower extreme position, thereby delivering fluid under pressure to'the bottom of the working cylinder 3'! to raise the ram 33. The ram will rise on its first stroke until it opens the limit switch S2. The opening of switch S2 opens relay R1, and the plungers of valves V1 and V2 return to the positions shown, so that oil under pressure is delivs ered to the upper end of the working cylinder 3'! for return of the ram 33. In this return move ment of the ram the ratchet wheel 54 is operated to shift the control cams 56 and 5? through approximately 120, thereby closing switches S1 and S3. From this point on the switch S2 has no control over the operation of the machine to completion of the cycle, the two other squeezing operations being independent of the limit switch S2 and controlled by the pressure switch S6. When the ram 33 is stopped by reason of the work offering resistance to movement of the gripping jaws, pressure is built up in the cylinder dd in which the plunger 99 for operating the pressure switch Se is disposed. This pressure is indicated on the gauge we, and the operator can alter the pressure at which switch S6 will be opened, to suit the work, by adjusting the plug iii! to increase or decrease the pressure of the spring Hi2 resisting movement of plunger 99. When the pressure is sunicient to overcome the resistance of the reacting spring M2, the switch S6 will be opened. This, in turn, causes opening of the relay R1- for the return stroke of the ram 33- The valves V1 and V2 return, as previously described, to the positions? shown. In this second return movement of the ram, the ratchet wheel 54 is again turned through approximately 120 to index the two control cams 56' and 51. to a 240 position from that shown. When the ram. 33 reaches the lower endv of itsstroheswitch S5 is closed causing the closing again of relay R1 and shifting of valve V1. and consequent shifting. of valve V2 for the next upstroke of the ram. At the upper end of the stroke the ram 33 will again exert a pressure dependent upon the adjustment of the reacting spring I02 for the plunger 99- operating the pressure switch S6, and when the switch S5 is opened by the building up of pres" surepa'st a predetermined value, relay R1 is again opened and valves V1 and V2 returned, as before, to the positions shown for the return stroke of the ram. 33'. In this downstroke, the ratchet wheel 54 is again indexed through approximately 120, thus returning the control cams 55 and 51 to the position illustrated. The opening of the switches S1 and S3, along with S4, completes the cycle and the machine stops. The work is then removed, if it has not been unloaded automatically, as previously described, and the machine is 8 then. ready for the commencement orv the next cycle.

It is believed the foregoing description conveys a good understanding of the objects and advantages of our invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

We claim:

1. Ina shell banding machine, the combination of a frame having a plurality of radial guides provided thereon, slides workin in said guides arranged to engage the work at their inner ends, said frame also having an axially extending guide, a ram working therein, a relatively movable piston and cylinder for operating the ram, a plurality of lever members pivotally supported on the frame intermediate their ends and operatively associated at one end with the slides and at the other end with the ram, wedge blocks on the ram, shoes pivotally mounted on the adjacent ends of the lever members and slidably engaging said wedge blocks, and spring pressed plungers on the frame having operative engagement with the lever members adjacent one end thereof to hold the shoes in close working contact with the wedge blocks, whereby the slides are operated positively in one direction by movement of the ram and. are spring returned under operation of the plungers.

2. In a shell banding machine, the combination of a frame having a plurality of radial guides provided thereon, slides working in said guides arranged to engage the work at their inner ends, said frame also having an axially extending guide, a ram working therein, a relatively movable piston and cylinder for operating the ram, a plurality of lever members pivotally supported on the frame intermediate their ends and operatively associated at one end with the slides and at the other end with the ram, said ram having inclined cam surfaces provided thereon, shoes pivotally mounted on the adjacent ends of said levers slidably engaging said surfaces, and spring means for maintaining close working contact between said shoes and said surfaces, where by the slides are operated. positively in their work strokes by movement of the ram and are returned to retracted position under spring action.

3. A shell banding machine comprising a frame having a plurality of radial guides provided thereon, slides working in said guides arranged to engage the work attheir inner ends, said frame also having an axially extending guide, a rain working therein, a relatively movable piston and cylinder for operating the ram, a plurality of lever members pivotally supported on the frame intermediate their ends and operatively associated at oneend with the slides and at the other end with the ram, said ram having inclined cam surfaces provided thereon, shoes pivotally mounted on the adjacent ends of said levers slidably engaging said surfaces, spring means for maintaining close working contact between said shoes and said surfaces, a source of pressure fluid, a magnetically operated valve means controlling the supply of pressure fluid to said cylinder to advance and retract said rain, a ram travel limit switch, apressure operated limit switch responsive to fluid pressure in said cylinder, means carried by said ram to actuate said ram travel limit switch, a rack gear on said last means, a pinion operated by said rack gear, a cycle control cam means actuated by said pinion, said ram travel limit switch and said pressure operated limit switch controlling the actuation'of said magnetically operated valve means to retract said ram, said cycle control cam means rendering said pres sure actuated limit switch inoperative during an initial stroke of said ram and rendering said ram travel limit switch inoperative during subsequent strokes of said ram in a. cycle of operation of the machine.

AXEL F. REHNBERG.

JOHN NELSON.

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